Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean.
The dynamics of phytoplankton species populations recorded during the 3-week, iron-fertilization experiment EisenEx carried out in spring in the Antarctic Polar Frontal Zone are presented and discussed as the difference between growth and mortality rates. Only two cosmopolitan diatom species, the ce...
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ftawi:oai:epic.awi.de:14859 2023-05-15T13:39:47+02:00 Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. Assmy, Philipp Henjes, Joachim Klaas, Christine Smetacek, Victor 2007 https://epic.awi.de/id/eprint/14859/ https://doi.org/10.1016/j.dsr.2006.12.005 https://hdl.handle.net/10013/epic.25072 unknown Assmy, P. , Henjes, J. orcid:0000-0002-6688-8802 , Klaas, C. orcid:0000-0002-6679-8970 and Smetacek, V. (2007) Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. , Deep Sea Research I:, 54 (3), pp. 340-362 . doi:10.1016/j.dsr.2006.12.005 <https://doi.org/10.1016/j.dsr.2006.12.005> , hdl:10013/epic.25072 EPIC3Deep Sea Research I:, 54(3), pp. 340-362 Article isiRev 2007 ftawi https://doi.org/10.1016/j.dsr.2006.12.005 2021-12-24T15:31:03Z The dynamics of phytoplankton species populations recorded during the 3-week, iron-fertilization experiment EisenEx carried out in spring in the Antarctic Polar Frontal Zone are presented and discussed as the difference between growth and mortality rates. Only two cosmopolitan diatom species, the centric Chaetoceros debilis and the pennate Pseudo-nitzschialineola, increased population density exponentially throughout the experiment to 150- and 90-fold of initial values, respectively. Because C. debilis initial abundance was tenfold lower than that of P. lineola, the two contributed 1% and 21% to bloom biomass, respectively at the end of the experiment, high-lighting the role of seeding in bloom formation. The other significant species increased population size at a linear rate throughout the experiment or for a short spurt phase to 3- to 18-fold of initial values. Conservative estimates of mortality rates within diatom species populations were obtained by comparing net accumulation rates of full cells with those of empty and broken frustules. The ratios were consistent over time for the various species but varied widely between them. The species-specific variation can be explained by differences in both growth and mortality rates, the latter partly due to either selective grazing or avoidance by the large protozoo- andmetazooplankton populations present. Selective predation by the abundant copepod populations on protistan grazers of diatoms (ciliates and heterotrophic dinoflagellates) apparently aided diatom biomass build-up. The response patterns of populations of the phytoplankton species present fall into six categories comprising disparate species, indicating that phylogeny is a poor predictor of ecology. The group that did not respond to fertilization was the most diverse and included both endemic and cosmopolitan as well as background and bloom-forming species. This lack of response to the advent of favorable growth conditions indicates that proximate factors during EisenEx triggered growth only in some species but had little effect on others. We attribute the differences in behavior to ultimate factors such as seasonal effects on life cycles and other internal constraints on growth rates. The implications for our understanding of the evolutionary ecology of phytoplankton and its impact on global biogeochemical cycles are pointed out. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Antarctic Southern Ocean The Antarctic Deep Sea Research Part I: Oceanographic Research Papers 54 3 340 362 |
institution |
Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
The dynamics of phytoplankton species populations recorded during the 3-week, iron-fertilization experiment EisenEx carried out in spring in the Antarctic Polar Frontal Zone are presented and discussed as the difference between growth and mortality rates. Only two cosmopolitan diatom species, the centric Chaetoceros debilis and the pennate Pseudo-nitzschialineola, increased population density exponentially throughout the experiment to 150- and 90-fold of initial values, respectively. Because C. debilis initial abundance was tenfold lower than that of P. lineola, the two contributed 1% and 21% to bloom biomass, respectively at the end of the experiment, high-lighting the role of seeding in bloom formation. The other significant species increased population size at a linear rate throughout the experiment or for a short spurt phase to 3- to 18-fold of initial values. Conservative estimates of mortality rates within diatom species populations were obtained by comparing net accumulation rates of full cells with those of empty and broken frustules. The ratios were consistent over time for the various species but varied widely between them. The species-specific variation can be explained by differences in both growth and mortality rates, the latter partly due to either selective grazing or avoidance by the large protozoo- andmetazooplankton populations present. Selective predation by the abundant copepod populations on protistan grazers of diatoms (ciliates and heterotrophic dinoflagellates) apparently aided diatom biomass build-up. The response patterns of populations of the phytoplankton species present fall into six categories comprising disparate species, indicating that phylogeny is a poor predictor of ecology. The group that did not respond to fertilization was the most diverse and included both endemic and cosmopolitan as well as background and bloom-forming species. This lack of response to the advent of favorable growth conditions indicates that proximate factors during EisenEx triggered growth only in some species but had little effect on others. We attribute the differences in behavior to ultimate factors such as seasonal effects on life cycles and other internal constraints on growth rates. The implications for our understanding of the evolutionary ecology of phytoplankton and its impact on global biogeochemical cycles are pointed out. |
format |
Article in Journal/Newspaper |
author |
Assmy, Philipp Henjes, Joachim Klaas, Christine Smetacek, Victor |
spellingShingle |
Assmy, Philipp Henjes, Joachim Klaas, Christine Smetacek, Victor Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. |
author_facet |
Assmy, Philipp Henjes, Joachim Klaas, Christine Smetacek, Victor |
author_sort |
Assmy, Philipp |
title |
Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. |
title_short |
Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. |
title_full |
Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. |
title_fullStr |
Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. |
title_full_unstemmed |
Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. |
title_sort |
mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment eisenex in the southern ocean. |
publishDate |
2007 |
url |
https://epic.awi.de/id/eprint/14859/ https://doi.org/10.1016/j.dsr.2006.12.005 https://hdl.handle.net/10013/epic.25072 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
EPIC3Deep Sea Research I:, 54(3), pp. 340-362 |
op_relation |
Assmy, P. , Henjes, J. orcid:0000-0002-6688-8802 , Klaas, C. orcid:0000-0002-6679-8970 and Smetacek, V. (2007) Mechanisms determining species dominance in a phytoplankton bloom induced by the iron fertilization experiment EisenEx in the Southern Ocean. , Deep Sea Research I:, 54 (3), pp. 340-362 . doi:10.1016/j.dsr.2006.12.005 <https://doi.org/10.1016/j.dsr.2006.12.005> , hdl:10013/epic.25072 |
op_doi |
https://doi.org/10.1016/j.dsr.2006.12.005 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
54 |
container_issue |
3 |
container_start_page |
340 |
op_container_end_page |
362 |
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1766123786281680896 |